Ribery, 31, has yet to feature in either of his country's warm-up friendlies since joining up with the squad, and underwent tests on the problem in a Paris hospital on Saturday in a bid to help speed his recovery.

However, he watched from the sidelines as his replacement on the left side of the front trio of Didier Deschamps' 4-3-3, Antoine Griezmann, scored in the 1-1 draw with Paraguay in Nice on Sunday.

France Television even reported on Sunday the Bayern Munich midfielder could announce he will miss the tournament ahead of the June 2 deadline for Deschamps to give FIFA his finalised 23-man squad list.

Deschamps replied "nothing new" to a question about Ribery's fitness, and insisted the ex-Marseille man could yet feature in his nation's final warm-up friendly against Jamaica in Lille next Sunday.

Giroud, however, told media the squad -- and even Ribery himself -- were now concerned over whether the influential attacking midfielder will be fit to face Honduras in his country's opening Group E game on June 15.

"He's starting to get irritated. I don't know if he's doubting, but he's worried and preoccupied with his situation," the Arsenal striker said. "We have to help him get through it and be patient. I go mad when I'm injured for three days. It's happened to him just before the World Cup."

Ribery is seen as fundamental to Les Bleus' cause in Brazil, and Loic Remy added: "Whether it's me or others, we try to make up for his absence as best we can, but he remains a key member of the squad."